Fusion reactivity ⟨σv⟩ is the whole game: it sets how much power a plasma of a given density and
temperature can make. These four curves are computed live from the verbatim Bosch–Hale coefficients in the
deposit's kronos_physics.py. D–³He turns on an order
of magnitude above D–T temperatures — that is the price. The payback: its products are charged, so their
energy can be steered to direct conversion instead of absorbed as neutron heat, and the neutron budget drops to
the 5.25 % the paper engineers for.
Log–log, 1–300 keV. The gold marker sits at the frozen Mode-C core ion temperature (65 keV). Hover for exact values. p–¹¹B uses the Nevins–Swain non-resonant fit — adequate for staging accounting; it remains the paper's gated Stage-3 endpoint, not a baseline claim.
The plain-language paper behind this instrument: Two Throttles: Near-Thermal Baseline, Hot-Ion Upside · The Fuel That Barely Bites: D-³He and the 5.25% Neutron Budget.